Japanese Patent Application Publication No. 2014-137298 discloses a fuel level gauge. The fuel level gage includes a rotator that rotates about a central axis, a fixing member that rotatably holds the rotator, a float that floats on a surface of fuel, and an arm that converts a vertical motion of the float into a rotary motion of the rotator. Two magnets fixed to the rotator. The magnets rotate about the central axis of the rotator. Each magnet is disposed to be spaced from the central axis of the rotator. A Hall element is housed in the fixing member.
A shaft hole is formed in the rotator coaxially with the central axis of the rotator. The shaft hole has a hole diameter smaller than a distance between the central axis of the rotator and each of the magnets. The fixing member has a shaft portion coaxially with the shaft hole. The shaft portion is fitted into the shaft hole to thereby allow the fixing member to rotatably hold the rotator.